1. Field of the Invention
The present invention relates to an optical pickup that reads the information recorded on the recording surface of an optical disc and records information on an optical disc.
2. Description of the Related Art
A general objective lens driving apparatus provided in the optical pickup in an optical disc drive is formed of: a lens holder in which an objective lens is mounted; a focusing coil, a tracking coil, and a tilt coil, which are attached to the lens holder; supporting members for supporting a moving part including the lens holder and these coils; a yoke; and a magnet.
When a driving current is supplied to the focusing coil, the moving part is driven, by electromagnetic force generated by an action with the magnetic flux from the magnet, in the focusing direction in which the moving part moves close to or away from the optical disc surface. Similarly, when a driving current is supplied to the tracking coil, the moving part is driven, by the electromagnetic force generated by an action with the magnetic flux from the magnet, in the tracking direction that is the radial direction of an optical disc. When a driving current is supplied to the tilt coil, the moving part is rotationally driven, by the magnetic force generated by an action with the magnetic flux from the magnet, in the radial tilt direction whose rotational axis is oriented toward the tangential direction of the optical disc.
A conventional example of such an objective lens driving apparatus is disclosed, for example, in Japanese Patent Publication Application No. 2010-40067. A configuration is described in Japanese Patent Publication Application No. 2010-40067, in which an objective lens driving apparatus is provided with a pair of tilt coils each having an approximately rectangular tube shape, which rotationally drive a lens holder in the radial tilt direction.
Because information equipment in each of which an optical disc drive is mounted, such as personal computers, are progressively being small in size and thin, optical disc drives and optical pickups are required to be thin. A reduction in power consumption is also required so that the information equipment can be used for a long time when carried.
In order to reduce the power consumption in an objective lens driving apparatus, it is needed to increase the driving force that is generated, in each of a focusing coil, tracking coil, and tilt coil, per current supplied to each of the coils.
In the aforementioned Japanese Patent Publication Application No. 2010-40067, however, it is only made that the tilt coil is formed into an approximately rectangular tube shape, and accordingly it is not sufficiently taken into consideration that the driving force generated in the tilt coil is increased.
An object of the present invention is to provide an optical pickup whose thickness is small and power consumption is low, these being achieved by increasing the driving force generated in the tilt coil in an objective lens driving apparatus and by making the thickness of the objective lens driving apparatus to be small.